Improvement in pneumatic car-brakes



2 Sheets-Sheet 1- D. MYERS & A. B. PULLMAN. PNEVUMATIGVOAR BRAKE.

No. 108,932. Patented Nov. 1, 1870.

. 2 Sheets-Sheet 2 D. MYERS 8; A; B. PULLMAN.

PNEUMATIC GAR BRAKE.

Patented Nov. 1, 1870.

DAVID MYERS AND ALBERT B. PULLMAN, or CHICAGO, ILLINOIS.

Letters Patent No. 108,932, dated November'l, 1870.

IMPROVEMENT lN PNEUMATIC CAR-BRAKES.

The Schedule referred to in these Letters Patent and making part of the same.

We, DAVID Mvnns and Annual 13. lurmtuxx, both of Chicago, in the county of Cool; and State of Illinois, have invented a new and useful Improvement in Pneumatic Gar-Brakes, of which the following is a specification, reterence being had to the accompanying drawing, which forms a part thereof.

Nature and Object of the Invention.

The first part of our invention relates to the vibrating-arm hinged to the ear to carry a friction-wheel so that it-can move vertically to the motion of the caraxle, and a combination of the friction-wheel with one .of the car-axles and an air-pump in such a manner that the motion of the axle operates thepump to pump air into the air-tank or reservoir, as hereafter more fully described. The object of this part of the invention is to cause the car while in motion to keep 1 p a constant power to apply the brake.

The second part of our invention relates to a novel device used in the place of an engine to apply the power. .It consists simply of a chamber, constructed as hereafter more fully. described, with expansible sides, into which the compressed air is admitted,

and, by itsazausing the chamber to expand, it moves the levers that apply the brakes. The object of this part of our invention is to make a cheap and durable device for transmitting the power of the compressed adr to the brake withoutusing the expensive engines commonly used.

The third part of our invention relates to the springarm attached to the p ump-rod for operating the p um p. The object of this invention is to allow this armto spring when a certain pressure of air is attained by ,pumping air into the reservoir, so that the pump will not make full strokes till the pressure in reservoir is reduced. The fourth part of our invention is the automatic 4 attachment to the valve that governs the admission of air into the part of the tank from which it is used to apply the brakes in such a manner as to so control the valve that when the atmosphere is damp .the valve will be opened with a less pressure in the tank than when .the atmosphere is dry. The object of this part of our invention is to so control the application of power that there will be less power appiied when the rails of the road are wet than when they are dry, in order to prevent setting the wheels and causing them to slip upon the rails.

Fifth our invent-ion relates to the oil-chamber and piston in the air-pump hereafter deseribed, the

' object of which is to cause the pump to be self-lubricating, which is essential in a car where there is so much dust.

Description of the Drawing.

Figure 1 is a vertical longitiuiinal sectional view of Figure 7, a side view of the ratchet-wheel, drum,

rope, and paw].

General Description.

A is an ordinary baggage-car commonly used on steam railways.

B is one of the car-axles.

We show only two two-wheel tracks, but two or more trucks may be used, and they may each contain any desired number of wheels.-

0 is the ii'iction-wheel, which is hung in the vibrating-arm l), and held to press against the axle 13 by the spring 1). The arm, being hinged to the car, will vibrate and allow the wheel to move vertically to conform to the motion of the axle,

This friction-wheel is upon a crank-shaft, F, which it revolves.

ll is the pitman connecting the crank F with the rock-shaft I, and

J is the spring-arm rigidly attached to the rockshaft I, and jointed to the pump-rod K, as shown.

When the car is in mot-ion the spring-arm J operates the pump till the pressure of air in the tank is sntiieient to cause the arm to spring, and thus prevent a full stroke of the pump; therefore the pump ceases pumping air into the tank.

The stiffness of the spring regulates the quantity i of air forced into-thetank.

These shafts and rods connnunicate motion from the axle through the il'iction-wheel to the air-pump, and they are so arranged that a slow motion is communicated, because that will pump air suilicicnt to apply the brakes in the ordinary running of a railway train.

L is the air-pump, aml is constructed the same as any ordinary air-pump, with the same valves for the ingress and egress of air.

'0, however, make the piston-valve M with projections, N, which extend down so as to dip into oil in the lower end of the pump; and they also rub against the interior of the pump as the piston-valve moves up and down. They, of course, take up oil and spread it'upon the interior of the pump at each stroke,- keeping it thoroughly lubricated.

There may be sufiicient oil carried in a reservoir .1 the pump to lubricate the pump for a long time.

is a pipe extending from the air-pump to the )\ver compartment 1 of the air-tank or reservoir.

The air is constantly being pumped into this tank ill there is sufiicient pressure to spring the arm J, as cove described.

Q is a pipe connecting the lower compartnieut l of he tank with the upper compartment It, the two ompartmcnts being separated by a diaphragm or parition.

S is a valve in the pipe Q, which is opened, as hereifter described, to allow the air to pass from the ower compartment 1 to the compartment R.

T is a lever, with its fulcrum at U, and

V is a rod connecting this lever to the valve 8..

\V is a piston-rod attached to the lever T and passng through an air-tight packing in the top of the :ompartmeut 1t.

It will be readily seen that as soon as a certain ircssnre of airis attained in the compartment 11-, by 'orcing air through the pipe Q, the piston \V is 'aisedgand the lever T is vibrated, which closes the -'alvc The power which is required 10 thus vibrate the ever T is regulated by the spring a, which is con- ;tantlyprcssing down on the lever 'l. to keep the valve ii open.

1f the spring (I is so regulated that the valve S is opt open ,till the pressure in the compartment It is forty pounds to the square inch, which pressure would raise the lever T and close the valve,'the pressurein the compartment 1 might be increased to any :xtent, say to even three or four hundred pounds to the square inch, and still the valve would remain closed; but as soon as the air. is used from the compartment Iii-to reduce the pressure therein, the valve is immediately opened and the air rushes in to keep the prcssnre at forty pounds.

I) is an air-pipe extending from the compartment R to the main air-pipe c, beneath the car; and

(l is a three-way valve in this. pipe,,to which a cord, 0, that extends to the engineer, is attached.

1' is a spring -for keeping this valve closed except when it is desired to apply the brakes.

There is a branch-pipe, g, beneath each of the cars, leading into the chamber h.

The chamber 71. is made with an outside ring, i, and flexible sidesj.

I nsually'make thesesidcs ol" rubber, and the edges resting upon the projection 7.: is securely fastened thereto bythe rings I and belts in, so as to pack them air tight.

These sides j are held and prevented from expanu inn only to a certain extent by the clamps a, several 0t which are secured to each disk 0 and the ring '0', as shown. v

\Vhen the compressed air allowed to pass throughthe pipe y into the chamber h, the sides are expanded, which, of course, moves the rod 1), which is connected with'the lever q.

This lever, when vilju-ated, applies the brakes through the ordinary brake-rods and levers r and s.

There is a slot, t, in the end of the rod 1), so that when the brake 'is applied by hand the lever q will vibrate without disturbing the rod q,,but when that red is moved as above described, it vibrates the lever and applies the bral. e.

' u are chains connected wheels for applying the brakes by hand.

The main air-pipe (J has a flexible tube, 2', at each end, to which a metallic coupling, 00, is attached.

These couplings are each provided, with valves, 3 and rods 2, which, when the cars are coupled, the rods strike against each other and open .the valves.

with the ordinary brakc- \Vhen the cars are uncoupled the springs 1 close the valves and prevent the air from escapin 2 are hooks for'coupling the couplers together.

3.3 is an ordinar cord or rope placed on the outside of the car when it is exposed to the action of the weather. It passes over the drum or pulley 4, and is attached to the spring 5, while the other end passes into the car and is attached to the lower end of the swinging arm 6 that the spring a, is on.

7 is a pawl, and it engages with the teeth 8, so as to prevent the drum 4 from turning in only one direction.

It will readily be seen that when the cord 3 becomes damp and shrinks and shortens, which would always be the case when the railway cars are wet, it moves the lower end of the arm 6 in the slot in the lever T, and less pressure would be required in the compartment R to move the piston W so as to vibrate the lever T and open the valve S.

When the rail and cord become dry again, the cord stretches and the spring 9 throws the arm 6'back to.

its original position; but if that does not take up all the slack in the rope 3, the spring 5 draws it around the drum' 4, and the pawl and ratchet-wheel prevent its being drawn back when it shrinks again.

In applying brakes to cars it is as much power as possible without setting the wheels, to cause them to slide upon the rails, and it is very important not to cause them to slide, as it wears flat places on their thread, which is very injurious to the wheels.

It requires considerable more power to set the wheels so as to cause them to slide when the rails are dry than when they are wet; therefore, we deem it important to have an automatic device that will vary the power that can be applied in such way that more power can be applied to the brake when the wheel and track are dry thauwhcn they are wet.

Instead of using one tank with two compartments, two tanks may be used, one receiving air from the pump and the other t'ed therefrom, as above described.

Claims.

What we claim, and desire to secure by Letters Patent, is-

1. The hinged arm 1) and friction-wheel 0, when constructed and arranged substantially as and for the purposes as described. i

2. The combination and arrangement of the arnr 1), wheel 0, the car-axle, the air-pump, and air-tank or reservoir 1, when constructed and arranged substantially as and for the purposes specified and shown.

3. The spring arm J, when constructed and arranged substantially as and for the purposes specified and shown.

4."The projections N attached to the piston-valve M of the pump, when constructed and operating subst-antially as and for the purpose described.

. 5. The expansible sidesj and clamps a, when 0011- structed and arranged substantially as and for the purpose described.

6. The cord or rope 3, in combination with the swinging arm 6, when constructed and arranged sub-%' stantially as and for the purposes described.

7 The drum 4, spring 5, pawl 7, and ratchet whecl 8, when arranged and operating substantially as and for the purposes described and shown. 1

DAVID MYERS. V ALBERT B.- PULLMAN.

Witnesses: I

L. L. 0013mm, HEINRIcH F. BRUNS.

essential to apply 

